Meta-Analysis of the Association of Urbanicity With Schizophrenia

Abstract

The association between urbanicity and risk of schizophrenia is well established. The incidence of schizophrenia has been observed to increase in line with rising levels of urbanicity, as measured in terms of population size or density. This association is expressed as Incidence Rate Ratio (IRR), and the results are usually presented by comparing the most urban with the most rural environment. In this study, we undertook to express the effect of urbanicity on the risk of schizophrenia in a linear form and to perform a meta-analysis of all available evidence. We first employed a simple regression analysis of log (IRR) as given in each study on the urbanicity category, assuming a uniform distribution and a linear association. In order to obtain more accurate estimates, we developed a more sophisticated method that generates individual data points with simulation from the summary data presented in the original studies, and then fits a logistic regression model. The estimates from each study were combined with meta-analysis. Despite the challenges that arise from differences between studies as regards to the number and relative size of urbanicity levels, a linear association was observed between the logarithm of the odds of risk for schizophrenia and urbanicity. The risk for schizophrenia at the most urban environment was estimated to be 2.37 times higher than in the most rural environment. The same effect was found when studies measuring the risk for nonaffective psychosis were included.

Neurodevelopment, GABA System Dysfunction, and Schizophrenia

“…There is evidence that prenatal maternal immune activation (MIA) (Brown and Derkits, 2010), perinatal hypoxia (Cannon et al, 2002;Schmidt-Kastner et al, 2012), adolescent cannabis use (Arseneault et al, 2004;Henquet et al, 2008), stress (Norman and Malla, 1993), obstetric complications (Dalman et al, 1999), urbanicity (Vassos et al, 2012), migrant status (Cantor-Graae and Selten, 2005), advanced paternal age (Malaspina, 2001), and others (Brown, 2011;Tandon et al, 2008) interact with predisposing genetics to increase risk for illness.…”

Childhood adversity and psychosis: generalised or specific effects?

“…In this respect, while research has generally prioritised factors such as childhood sexual abuse (CSA), physical abuse (CPA) and physical neglect (CPN), greater attention is now being paid to other forms of adversity. For example, recent meta-analyses have proposed a heightened risk of psychotic symptoms in association with such factors as peer bullying (van Dam et al 2012), parental communication deviance and urbanicity (Vassos et al 2012). Empirical work with large cross-sectional datasets have likewise emphasised the potential role of deprivation and social inequalities and being raised in institutional care in predicting psychotic symptoms, as well as the role of attachment quality in mediating between adversity exposure and subsequent psychosis .…”

Effect of Antipsychotic Drugs on Body Composition in Patients Attending Psychiatry Clinic, Jimma, Ethiopia

“…Antipsychotic drugs fall into two major groups: first generation antipsychotics and second generation antipsychotics [10,11]. Most of the newer atypical agents appear to exert part of their unique action through inhibition of serotonin receptors (5HT), particularly 5-HT2A receptors [12].…”